BR112018011253B1 - Molding machine and method for molding a part - Google Patents

Abstract

MOLDING MACHINE, AND, METHOD FOR MOLDING A PART. The present description provides a molding machine and a method for molding a part. The molding machine comprises a first mold half and two or more extruders associated with the first mold half, each extruder of the two or more extruders including a barrel, an extrusion screw within the barrel and a nozzle in sealed engagement with the first. half of the mold, wherein each extruder of the two or more extruders is independently controlled to rotate the extrusion screw in a first direction to cause material flow and to rotate the extrusion screw in a second direction opposite to the first direction to stop flow of material. material once the targeted pressure is reached for the respective extruder.

Description

CROSS-REFERENCES OF RELATED PATENT APPLICATIONS

[001] This patent application claims priority from the U.S. Patent Application. No. 15/177,302 entitled “Molding Machine and One-Piece Molding Method,” filed June 8, 2016 which is a continuation-in-part of the U.S. Patent Application. number 14/959,921 entitled “Injection molding system and method of manufacturing a component”, filed December 4, 2015, is a continuation-in-part of International Patent Application number PCT/US2015/064045 entitled “ Injection Molding System and One-Component Fabrication Method”, filed December 4, 2015, is a continuation-in-part of the U.S. Patent Application. number 14/960,115 entitled “Nozzle Switch for Injection Molding System”, filed December 4, 2015, is a continuation-in-part of International Patent Application, number PCT/US2015/064110, entitled “Nozzle Switch nozzle for injection molding system”, filed December 4, 2015, is a continuation-in-part of the U.S. Patent Application. number 14/960,101 entitled “Control System for Injection Molding”, filed December 4, 2015, and is a continuation-in-part of International Patent Application, number PCT/US2015/064073, entitled “Control System for injection molding”, filed December 4, 2015, each of which claims benefit under 35 U.S.C. 119(e) of the U.S. Provisional Patent Application No. 62/087,414 entitled “Extrude-fill and extrude screw injection molding,” filed December 4, 2014, U.S. Provisional Patent Application. No. 62/087,449, titled “Nozzle Switch for Extrude-Fill Molding System,” filed December 4, 2014, and U.S. Provisional Patent Application. No. 62/087,480, entitled “Extrude-fill Injection Molding Control System,” filed December 4, 2014, the applications for which are incorporated herein by reference in their entirety.

FIELD

[002] The present description is directed, generally, to molding machines. More specifically, the present description is directed to a molding machine and method for molding a part.

FUNDAMENTALS

[003] A traditional injection molding system melts a material, such as a plastic, primarily by shear heat that is dynamically generated by rotation of an extrusion screw. The dynamically generated shear heat in the traditional injection molding system is dependent on the use of petroleum-derived plastic resins of a high level of purity and consistency. FIG. 1 is a schematic diagram for a traditional injection molding system 100. An injection zone 112 is located ahead of an extrusion screw 102 to retain a molten material prior to injection. A check ring 104, or check valve, is used to allow the melt to flow forward during a recovery extrusion stage that resides between the injections, and to prevent the melt from flowing back into the extrusion screw 102. Backflow can occur when injection pressure is applied to the melt. The material can be melted using primarily heat shear. For example, the fused state can be created for approx. 75% shear heat and approx. 25% conduction heat generated from 114 belt heaters.

[004] Traditional extrusion screw 102 is designed with a large pitch 132 to promote shear heat generation and mix hot and cold plastic. As shown in FIG. 1, a diameter of the root 134 of the screw 102 is narrower near a hopper 106 which is fed raw material through an inlet of a cylinder 110. Along the length of the extrusion screw towards the nozzle 108, the diameter of the The root increases to create a compression zone to promote the generation of shear heat. A fillet height 136 of screw 102 decreases towards nozzle 108, which reduces the space between screw 102 and cylinder 110.

[005] During a recovery extrusion stage, the molten material is transported along the length of the screw 102 to the injection zone 112 present in the cylinder 110 by rotating the extrusion screw using a motor 150. The injection zone 112 is located in between a nozzle 108 and the check ring 104 at the end of the extrusion screw 102. The molten material is confined in the injection zone by the cold raw mass, which seals the nozzle 108 after the injection cycle and prevents the plastic from flowing into the injection zone. into a mold 140 through a port 146 and feed channels 142 during the recovery extrusion stage.

[006] During an injection cycle, screw 102 is driven forward without rotation under very high injection pressure by cylinder 138. Screw 102 and check ring 104 can work together as a piston to inject molten material into the mold. The recovery extrusion stage can only take 10-25% of the complete molding time, such that shear heat can also be lost when the extrusion screw does not rotate, except during the recovery extrusion stage.

[007] The traditional injection molding system 100 is based on the formation of a cold raw mass in the nozzle 108 between each injection. The cold stock of plastic causes one of the biggest inefficiencies for the traditional injection molding system 100. The cold stock requires very high pressure to dislodge it from the nozzle 108 and allow a molten material to flow into a mold cavity. . A high injection pressure is required to propel the molten material into the mold cavity through the feed channels 142. An injection pressure of between 137.90 to 206.84 MPa (20,000 to 30,000 psi) is commonly required in order to to obtain a pressure of 3.45 to 10.34 MPa (500 psi to 1,500 psi) in the mold cavity. Due to the high injection pressure, the traditional injection molding system 100 requires the cylinder wall to be thick 110, which reduces heat conduction to the material from the belt heaters 114 that surround the cylinder 110.

[008] The traditional injection molding system 100 may use either a hydraulic system or an electric motor 128 to power a gripping system 120, which may include stationary press plates 122A-B, a movable mold holder 124 and rods. connector 126. A gripping cylinder 130 applies sufficient pressure to hold the mold closed during injection. The traditional injection molding system requires large and expensive power sources for the injection system 118 and for the gripping system 120. These power sources need to be supported by a massive machine structure, which increases infrastructure infrastructure costs. installation, including power supply, thick concrete foundations or floors, and oversized HVAC systems that are expensive to purchase, operate and maintain.

[009] The shear heat generated by the traditional injection molding system limits its ability to mold certain materials such as bio-based plastics. Bio-based plastics are degraded by the pressures applied to the traditional injection molding system, reacting adversely to the pressure the machine generates to create shear heat in the petroleum-based plastics injection molding process. A newly developed injection molding system described in U.S. Patent. number 8,163,208, entitled “Injection Molding Method and Apparatus” by R. Fitzpatrick, uses static heat conduction to melt the plastic instead of shear heat. The system described can mold bio-based plastics into small parts. Specifically, the system described includes a piston that is positioned within a tubular screw and runs through the center of the circular screw. In general, moving the entire screw forward during the injection cycle would require a large injection cylinder. In the described system, the entire screw of a larger diameter does not move. Only the piston is advanced, which requires a much smaller injection cylinder to apply force to the piston. The described system retrieves and transports the molten material in front of the piston between each shot or injection cycle, and injects the molten material into a mold from the piston. The part size is determined by the piston area multiplied by the piston stroke length which defines the volume during injection, but that part size is limited by the small piston displacement volume, normally approx. 3-5 grams of plastic, which is a small shot size. It is desirable to mold parts with unlimited shot sizes.

[0010] Likewise, the traditional injection molding system 100 requires a manual purge operation by experienced start-up operators. For example, an operator may first turn on the cylinder heaters 114 and wait until the screw 102 embedded in the plastic or resin is loosened to allow the screw motor 150 to start. A purge process is required to generate initial shear heat. The purge process begins when the operator turns screw 102 to move resin forward, and screw 102 is driven back to its injection position. The operator then activates the injection force to drive screw 102 forward, allowing resin to exit nozzle 108 into the base of the machine. The cycling process is repeated to generate initial shear heat until the resin leaves the nozzle 108, which suggests that the material may be hot enough that the operator can start molding. Manual operation is highly subjective and requires skilled operators to start machines and adjust molding processes. Subsequent molding operations need to be consistent and uninterrupted to satisfy the shear heat generation requirements.

[0011] Documents that can be related to the present description, as they include various injection molding systems, are the U.S. Patent. No. 7,906,048, U.S. Patent No. 7,172,333, U.S. Patent No. 2,734,226, U.S. Patent No. 4,154,536, U.S. Patent number 6,059,556 and U.S. Patent number 7,291,297. These propositions, however, can be improved.

BRIEF SUMMARY

[0012] The present description generally provides a molding machine, which may be referred to herein as an extrude-fill (ETF) molding machine, and a one-piece molding method. In some embodiments, the molding machine may include multiple molding systems (e.g., extruders) for pumping molten material into one or more mold cavities. Multiple molding systems can pump the same or different materials into one or more mold cavities. Multiple molding systems can be controlled individually and/or collectively. In some embodiments, a method of molding a part may include pumping material into one or more mold cavities through multiple molding systems, ceasing to pump material into one or more mold cavities when one or more pressures associated with the multiple molding systems, and releasing a molded part from said one or more mold cavities after said one or more pressures are reached.

[0013] In some embodiments, a molding machine may include a first mold half and two or more extruders associated with the first mold half. Each extruder of the two or more extruders may include a barrel, an extrusion screw within the barrel, and a nozzle in sealed engagement with the first mold half. Each extruder of the two or more extruders can be independently controlled to stop the flow of material once a target pressure is reached for the respective extruder. The first mold half may define a single mold cavity, and each extruder of the two or more extruders may be in fluid communication with the single mold cavity. The first mold half defines two or more mold cavities, and each extruder of the two or more extruders may be in fluid communication with a different mold cavity of the two or more mold cavities. The molding machine may include a single hopper operatively coupled to the two or more extruders for feeding the two or more extruders. The molding machine may include a manifold operatively coupled to the single hopper and the two or more extruders to divert material to the respective extruders of the two or more extruders. The two or more extruders can be arranged in a die. The two or more extruders may be oriented substantially parallel to each other, and at least two of the two or more extruders may be positioned one above the other along a vertical dimension of the first mold half. The molding machine may include a controller that monitors the pressure for each extruder of the two or more extruders and is configured to release a gripping force applied to the first half of the mold to release a molded part therein as each extruder of the two or more more extruders reach their target pressure. The target pressure for each extruder of the two or more extruders may be based on the area of the first mold half into which the respective extruder is extruding material. The two or more extruders may include four or more extruders spaced apart. The two or more extruders can be identical or different from each other. The two or more extruders may be operable to extrude the same or different materials into the first mold half.

[0014] In some embodiments, a molding machine includes a first mold half, a first extruder associated with the first mold half, and a second extruder associated with the first mold half. The first extruder may include a first barrel, a first extrusion screw within the second barrel, and a second nozzle in sealed engagement with the first mold half. The second extruder may include a second barrel, a second extrusion screw within the second barrel, and a second nozzle in sealed engagement with the first mold half. The first and second extruders can be independently controlled to cease material flow through the first and second extruders once the first and second pressures are reached for the first and second extruders, respectively. The first mold half may define a single mold cavity, and the first and second extruders may be in fluid communication with the single mold cavity. The first mold half can define a first mold cavity and a second mold cavity, the first extruder can be in fluid communication with the first mold cavity, and the second extruder can be in fluid communication with the second mold cavity. The molding machine may include a single hopper operatively coupled to the first and second extruders to supply material to the first and second extruders. The molding machine may include a manifold operatively coupled to the single hopper, the first extruders and the second extruders to divert material to the first and second extruders. The first and second extruders may be oriented substantially parallel to each other and substantially perpendicular to the first mold half. The molding machine may include a third extruder and a fourth extruder. The first, second, third and fourth extruders can be arranged in a die. The first, second, third and fourth extruders can be spaced evenly apart. The molding machine may include a controller that monitors the pressure of the first and second extruders and configured to release a gripping force applied to the first mold half to release a part molded therein once the first and second pressures are reached. The first and second extruders can be identical or different from each other. The first and second extruders may be operable to extrude the same or different materials into the first mold half. In some embodiments, a method of molding a part includes extruding a first material through a first nozzle of a first extruder in sealed engagement with a first mold half, extruding a second material through a second nozzle of a second extruder in sealed engagement with the first mold half, ceasing the extrusion of the first material through the first nozzle when a first pressure associated with the first extruder is reached, ceasing the extrusion of the second material through the second nozzle when a second pressure associated with the second extruder is reached and releasing a molded part from the first mold half after both the first and second pressures are achieved. The extrusion of the first material and the extrusion of the second material may include extruding the first and second materials into the same cavity defined by the first mold half. The extrusion of the first material and the extrusion of the second material may include extruding the first and second materials into different cavities defined by the first mold half. The first press is different from the second press. The first extruder may be identical or different from the second extruder.

[0015] Additional modalities and features are expressed in part in the following description and will become apparent to those skilled in the art upon examination of the report, or may be learned by practice of the subject matter described. A fuller understanding of the nature and advantages of the present invention may be understood by referring to the remaining portions of the report and drawings, which form part of this description.

[0016] The present description is provided to aid understanding, and a person skilled in the art will understand that each of the various aspects and features of the description may be used to advantage in some cases, or in combination with other aspects and features of the description in others. cases. Therefore, while the description is presented as modalities, it is important to recognize that individual aspects of any modality may be claimed separately or in combination with aspects and features of that modality or any other modality.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The description will be more fully understood by referring to the figures and data graphs, which are presented as various modes of description and should be interpreted as a complete recital of the scope of the description, in which: FIG. 1 is a schematic diagram of a traditional injection molding system.

[0018] FIG. 2A is an extrusion screw molding system in accordance with the embodiments of the present description.

[0019] FIG. 2B is a sectional view of the molding system of FIG. 2A in accordance with the embodiments of the present description.

[0020] FIG. 2C is a perspective view of the molding system of FIG. 2A prior to assembly in accordance with the embodiments of the present description.

[0021] FIG. 3A is a sectional view of a molding system including induction heating in accordance with the embodiments of the present description.

[0022] FIG. 3B is a sectional view of the molding system of FIG. 3A including a thermally insulating jacket in accordance with the embodiments of the present description.

[0023] FIG. 3C is a sectional view of the molding system of FIG. 3B including an insulating air gap between the liner and an internal tubular structure of the cylinder in accordance with the embodiments of the present description.

[0024] FIG. 4A is a stepped screw extrusion molding system in accordance with the embodiments of the present description.

[0025] FIG. 4B is a sectional view of the molding system of FIG. 4A in accordance with the embodiments of the present description.

[0026] FIG. 5 is a perspective view of the molding system of FIG. 4A prior to assembly in accordance with the embodiments of the present description.

[0027] FIG. 6A illustrates an extrusion screw having a sharp geometry in accordance with the embodiments of the present description.

[0028] FIG. 6B illustrates an extrusion screw having a less sharp geometry in accordance with the embodiments of the present description.

[0029] FIG. 7 is a flowchart illustrating steps for molding a part in accordance with the embodiments of the present description.

[0030] FIG. 8A is a perspective view of a molding system with a shuttle table in a first position in accordance with the embodiments of the present description.

[0031] FIG. 8B is a perspective view of a molding system with a shuttle table in a second position in accordance with the embodiments of the present description.

[0032] FIG. 9 is a simplified diagram illustrating a molding machine including multiple molding systems in accordance with the embodiments of the present description.

[0033] FIG. 10 is a perspective view of a molding machine including multiple molding systems in accordance with the embodiments of the present description.

[0034] FIG. 11 is a sectional view of the molding machine of FIG. 10 taken along line 11-11 in FIG. 10 and illustrates a flow path from a hopper to multiple molding systems in accordance with the embodiments of the present description.

[0035] FIG. 12 is a perspective view of the multiple molding systems of FIG. 10 coupled with a mold half defining multiple mold cavities in accordance with the embodiments of the present description.

[0036] FIG. 13 is a perspective view of the multiple molding systems of FIG. 10 coupled with a mold half defining a single mold cavity in accordance with the embodiments of the present description. DETAILED DESCRIPTION

[0037] The present description may be understood by referring to the following detailed description, taken in conjunction with the drawings as described below. Note that, for purposes of illustrative clarity, certain elements in various drawings may not be drawn to scale.

[0038] The present description generally provides a molding machine, which may include a molding system and a gripping system. The molding system may include an extrusion screw that extrudes on demand to transfer or pump molten material into a mold with an unlimited or variable shot size or displacement volume, without requiring a purge process after periods of downtime. In traditional injection molding systems, the shot size is fixed and is the volume of material that can be displaced or transferred into the mold during an injection cycle, sufficient to fill a single mold cavity or a plurality of mold cavities. . The variable shot size of the ETF molding system is different from the shot size of traditional fixed injection molding systems, in which the shot size is predetermined by the screw diameter and the injection stroke length, which is the axial distance. traversed by the traditional screw 102 (see FIG. 1) during an injection cycle. The traditional injection molding system 100 (see FIG. 1) performs a sequential and fixed process in which shot size changes require changes in control settings. The ETF molding system can extrude plastic for a specific time, until a specific mold cavity pressure is reached, until a specific screw back pressure is reached, until a specific screw torque load is reached, or by a predetermined number. -Selected screw rotations to shape parts with various dimensions to provide any desired shot size.

[0039] The ETF molding system can use heat conduction to produce a homogeneous melt (eg, a molten resin material) with substantially reduced shear heat generation. The melt can be heated to a desired viscosity. Upon reaching the desired viscosity in a static state, lower extrusion pressure may be required to fill the mold cavity. Likewise, a lower gripping force may be required for gripping and retaining the mold.

[0040] The ETF molding system may include a screw designed to function as a transfer pump for extrusion of molten material under pressure high enough to fill a mold cavity. The screw can rotate in two opposite directions. One of the benefits of reverse screw rotation is to help stir and mix the resin. When the extrusion screw rotates in one direction to pump resin material into a mold cavity, a flow and pressure pattern can be established. Reversing the screw rotation can interrupt the flow pattern and interrupt the hysteresis of the resin material, which can decompress the cylinder between molded part shots and can allow more precise control of the molding system. The screw can conduct heat to the material inside a cylinder. For example, screw reversal can mix the resin material to increase heat conduction to achieve a more consistent melt viscosity and ensure a more uniform extruder. The screw may include an internal heat source, such as a heater placed within the screw, to assist in conducting heat to the material within the cylinder. The screw may be formed of a thermally conductive material, such as bronze, to efficiently conduct heat from the internal heat source into the material. In some embodiments, the screw may alternate along the axial direction to open or close a nozzle and allow or prevent, respectively, flow of resin material into a mold cavity.

[0041] The molding system can extrude material without the high pressures, commonly 137.90 to 206.84 MPa (20,000 and 30,000 psi), found in the traditional 100 injection molding system. The 100 traditional injection molding system uses thick-walled cylinders and heavy-duty screws designed to generate and contain high pressure and move material within the high pressure system 100. When operating at lower pressures, which can be as low as 5-10% above the pressure at a associated mold cavity, the ETF molding system can be constructed from non-traditional materials and configurations that support significantly lower pressures. The lower pressure requirements of the molding system can facilitate the use of non-traditional materials, which can be softer and lighter than traditional materials. For example, the screw in the molding system can be constructed with significantly less mass due to the lower pressure environment, and therefore can create less heat reduction in the center of the system when external heat sources are used. Non-traditional materials can improve thermal conductivity or insulation, improve surface friction coefficient, or other properties like these, which can improve the casting and pumping of materials through the molding system. For example, the screw and/or cylinder may be made of thermally conductive materials that are not used in traditional injection molding systems due to lack of strength, such as bronze alloys, copper alloys, and copper-nickel alloys. .

[0042] FIG. 2A illustrates a molding system 200 in accordance with the embodiments of the present description. FIG. 2B is a sectional view of the molding system 200 illustrated in FIG. 2A. FIG. 2C is a perspective view of components of the molding system 200 illustrated in FIG. 2A before assembly.

[0043] Referring generally to FIGS. 2A-2C, the molding system 200 may include an extrusion screw 202 positioned within a cylinder 210 (see FIG. 2B). A hopper block opening 216 may be associated with cylinder inlet 226 for transferring material, usually in the form of pellets, from a hopper block 206 to cylinder 210, and a nozzle 208 may be associated with one end of the cylinder. 210 for transferring molten material from cylinder 210 to a mold. One or more heaters 214 can heat material within cylinder 210 to a molten state, and extrusion screw 202 can rotate within cylinder 210 to pump material along a length of cylinder 210 and into the mold. A motor or other drive system may be used to rotate the extrusion screw 202. A cylinder may be coupled to the extrusion screw 202 or cylinder 210 to move either screw 202 or cylinder 210 in an axial direction relative to the other. screw 202 or cylinder 210 in order to open or close mouthpiece 208.

[0044] The molding system 200 may be associated with a gripping system, which may include a cylinder or an electric motor to power the gripping system. The gripping system may include one or more stationary press plates, a movable mold holder, and one or more connecting rods. A gripping cylinder can apply pressure to the movable mold holder to hold a mold closed during extrusion of molten material from the nozzle 208 of the molding system 200 into the mold. Molding system 200 may primarily use static heat conduction, rather than shear heat generation, to melt the material within cylinder 210. Upon achieving a desired viscosity using primarily static heat conduction, lower pressure may be required to extrusion of material into the mold and thus a lower gripping force can hold the mold in a closed position. As such, the molding system 200 and gripping system, including the cylinder or electric motor to power the gripping system, may be smaller and require less energy to operate than the traditional injection molding system 100, which requires generally large and expensive sources of energy for both the injection system 118 and the gripping system 120 (see FIG. 1). The power source for the traditional 100 injection molding system typically needs to be supported by a massive machine frame, which increases facility infrastructure costs, including power supply, thick concrete foundations or floors, and HVAC systems. that are expensive to acquire, operate and maintain.

[0045] Referring further to FIGS. 2A-2C, cylinder 210 of molding system 200 may include extrusion screw 202. Further details on extrusion screw are shown in FIG. 2C. A gap between the extrusion screw 202 and the cylinder 210 can be dimensioned to prevent the generation of shear heat and allow the rotation of the extrusion screw 202 within the cylinder 210. The cylinder 210 can allow an axial movement of the extrusion screw 202 inside cylinder 210.

[0046] The molding system 200 can operate at a lower pressure than the traditional injection molding system 100. The lower operating pressure can allow the cylinder 210 to have a thin wall, which can provide better heat conduction to the material inside. of cylinder 210 (see FIGS. 2A-2C) than the thick wall of traditional cylinder 110 (see FIG. 1). For example, the wall thickness of cylinder 210 may be 0.32 to 0.63 cm (0.125 inches to 0.250 inches) thick, compared to a wall thickness of cylinder 110 of 1.90 to 5.08 cm ( 0.750 inches to 2.00 inches) from the traditional injection molding system 100 (see FIG. 1). Static heat conduction, along with a gripping nozzle and screw tip discussed below, can reduce cylinder internal pressure compared to the traditional 100 injection molding system.

[0047] Materials for forming cylinder 210 may be selected on the basis of heat conduction rather than pressure containment as a result of low extrusion or injection pressure. For example, cylinder 210 may include magnetic material for inductive heating or highly conductive material, such as bronze, copper, aluminum or their alloys. In some embodiments, cylinder 210 may be formed of steel.

[0048] Hopper block 206 of molding system 200 of FIGS. 2A-2C may include an opening 216 coupled to an inlet 226 of cylinder 210. Hopper block 206 may include a hollow portion 217 configured to slide over cylinder 210. Hopper block 206 and cylinder 210 may be mounted in such a way. such that material in hopper block 206 may be drawn from or fed into cylinder 210 through hopper block opening 216 and inlet cylinder 226. Hopper block 206 may include one or more cooling channels 218 for circulating fluid fluid. cooling, such as water, water-based compounds, or other cooling compounds, such as the extrusion screw 202, and the cylinder 210 next to the hopper block 206 can remain cold, for example, at room temperature.

[0049] Molding system 200 can heat material within cylinder 210 to prepare material for extrusion into a mold. For example, as illustrated in FIGS. 2A-2C, molding system 200 may include some external heaters, such as belt heaters 214A-214C, for heating material within cylinder 210. Belt heaters 214A-214C may be located within cylinder 210 and may conduct heat through cylinder 210 to material located within cylinder 210. By heating cylinder 210, belt heaters 214A-214C can transfer sufficient heat to material located within cylinder 210 to melt the material for extrusion into a mold. Heat from belt heaters 214A-214C may be conducted through cylinder 210 and radiated into an annular space defined between cylinder 210 and screw 202 in which material is received. The heat from the heated annular space can be transferred to the screw 202, which in turn can heat the material along an interface between the screw 202 and the material. Screw 202 may include threads disposed adjacent an inside diameter of cylinder 210, and thus heat from cylinder 210 may be conducted through threads of bolt 202 to heat material within cylinder 210. The height of the bolt threads can define the depth of the annular space between screw 202 and cylinder 210. As illustrated in FIGS. 2A and 2B, belt heaters 214A-214C may encompass cylinder 210 when molding system 200 is assembled to transfer heat to material within cylinder 210. Belt heaters 214A-214C may be electrical heaters.

[0050] Referring to FIGS. 2A and 2B, the belt heaters 214A-214C may be spaced along a length of the cylinder 210. The belt heater 214C closest to the hopper block 206 may be placed at a distance from a cylinder collar 220 which may include two portions 220A and 220B at a front end of hopper block 206. Referring to FIG. 2B, the belt heater 214C may be placed at a distance from the hopper block 206 such that a temperature transition region 222 in the cylinder 210 can be present between the hopper block 206 and a heated region 224 where the heaters 214A -C are located. In the temperature transition region 222, the material can remain relatively cool and can act as a seal between the outside diameter of the screw 202 and the inside diameter of the cylinder 210 to guide the molten material in the heated region 224 to a mold and continuously transport the material for flow in the mold. The temperature transition region 222 may be designed such that the material in the transition region 222 has sufficient volume to act as a seal to guide the molten material in the heated region 224 into a mold. For example, temperature transition region 222 may include a length that may vary depending on the application of molding system 200, and may be determined on a case-by-case basis. By maintaining a suitable temperature transition region 222 between the cold material entering the cylinder 210 from the hopper block 206 and the molten material in the heated region 224, the cold material and the transition material can work with the mixing screw 202 to providing an extrusion force to pump the molten material into the heated region 224. When the molten material is too close to the hopper 206, the extrusion force may be lost. The presence of an adequate amount of cold material in the temperature transition region or zone 222 can ensure that the cold material will slide along the screw geometry to move the molten material along the heated region 224 towards the mold. If the cold material does not slide along the screw in the transition zone 222, then the molten material can stick to the screw 202 in the heated region 224 and can rotate around inside the cylinder 210 with the screw 202.

[0051] The molding system 200 may include an internal heat source for heating the material located within the cylinder 210. Referring to FIG. 2B, one or more resistive heaters 225, such as cartridge heaters, can be received within the screw 202. The resistive heaters 225 can internally heat the screw 202, and the screw 202 can transfer heat to the molding material located between the screw 202 and cylinder 210. Molding system 200 may include multiple resistive heaters 225 arranged axially along a length of screw 202, and resistive heaters 225 may be independently controlled to provide varying temperatures along the length of the screw. The molding system 200 may include a friction ring to release electrical energy to the resistive heaters 225. The friction ring may include a fixed end for power connection, and a rotating end that rotates with screw 202 to provide electrical connectivity to the resistive heaters 225 while screw 202 is rotating. A thermocouple may be added to provide feedback to control the resistive heaters 225, and the friction ring may provide thermocouple wire connection to provide thermocouple readings for the most efficient conduction of heat to the material between the screw 202 and the cylinder. 210.

[0052] In some embodiments, the molding system 200 may heat the molding material between the screw 202 and the cylinder 210 through induction heating to facilitate rapid heating of the molding material. In the description below, elements or components similar to those in the embodiment of FIGS. 2A-2C are designated with the same reference numbers increased by 100 and therefore redundant descriptions are omitted. Referring to FIGS. 3A-3C, a molding system 300 may include a magnetic screw 302 and/or cylinder 310. The screw 302 and/or cylinder 310 may be heated by electromagnetic induction caused by an alternating magnetic field generated by an induction heater. The induction heater may include an electromagnet, such as an inductive heating coil 340, and an electronic oscillator may pass an alternating current through the electromagnet to generate an alternating magnetic field that penetrates and heats the screw 302 and/or cylinder 310 to, thereby heating the raw material located between the screw 302 and the cylinder 310. As illustrated in FIGS. 3A-3C, inductive heating coil 340 may surround cylinder 310 to generate a magnetic field that heats screw 302 and/or cylinder 310. Screw 302 and/or cylinder 310 may be formed from a magnetic material. , such as carbon steel, for interacting with the magnetic field, thereby heating screw 302 and/or cylinder 310. In some embodiments, screw 302 and/or cylinder 310 may be formed at least partially of a ferromagnetic material , which can result in at least a portion of the screw 302 and/or the cylinder 310 being magnetic. Induction heating can be used to facilitate faster response time than electric heaters, and induction heating can instantly or rapidly heat screw 302 and/or cylinder 310. In some embodiments, screw 302 and/or cylinder 310 may include at least one magnetic portion or section to facilitate faster response time. In some embodiments, cylinder 310 may be constructed from a magnetic material to promote inductive heating and may work in concert with screw 302, such as a magnetic material placed within screw 302. A heat source may be the material of the screw 302. screw 302, cylinder 310, and/or a cylinder cover 310 acting with a magnetic field generated by an electromagnet (such as an inductive heating coil 340) to create induction heating.

[0053] In some embodiments the screw 302 may be formed of a magnetic material for interaction with the magnetic field of the electromagnet, such as the inductive heating coil 340, and the cylinder 310 may be formed of ceramic, a carbon fiber, fiber glass, or other thermally insulating material. For example, as illustrated in FIG. 3A, the electromagnet, such as the inductive heating coil 340, can inductively heat the screw 302, which, in turn, can heat the molding material disposed between the screw 302 and the cylinder 310. The cylinder 310 can thermally insulate the molding material and screw 302 to retain heat within the space defined between screw 302 and cylinder 310.

[0054] Referring to FIGS. 3B and 3C, cylinder 310 may include an insulating liner 342 surrounding an internal tubular structure 343. Liner 342 may be formed of ceramic, carbon fiber, fiberglass, or other thermally insulating material to insulate and control the environment within the cylinder. cylinder 310. Liner 342 may circumferentially contact internal tubular structure 343, as illustrated in FIG. 3B, or the liner 342 may be spaced radially from the inner tubular structure 343 by an insulating air gap 344 to further retain heat within the cylinder 310. In the illustrative embodiments of FIGS. 3B and 3C, the inner tube structure 343 may be formed of a thermally insulating material to insulate the environment within the cylinder 310. Alternatively, the inner tube structure 343 may be formed of a magnetic material, such as carbon steel, to interact with the magnetic field of the electromagnet, such as the inductive heating coil 340, and can heat the molding material in line with the screw 302, and the jacket 342 can retain heat within the cylinder 310.

[0055] Referring further to FIGS. 3A-3C, screw 302 may define an at least partially hollow core for receiving a single heat source or a plurality of heat sources to obtain specific heat profiles within screw 302. For example, screw 302 may be formed at least partially of a magnetic material and/or including a magnetic material, such as one or more magnetic inserts, within the screw 302. As illustrated in FIGS. 3A-3C, one or more magnetic inserts 325 may be received within screw 302. Said one or more inserts 325 may interact with the magnetic field of inductive heating coil 340 to internally heat screw 302. Inserts 325A-325C may have different sizes or mass to provide different heat generation along the length of screw 302.

[0056] As illustrated in FIGS. 3A-3C, inserts 325A-325C may be positioned along the length of screw 302 such that the larger insert 325A is located near the tip of the screw 302, the smaller insert 325C is located near the hopper block 306, and the middle insert 325B is located intermediate the other inserts 325A, 325B. The 325A insert located near the tip of the screw 302 may be larger in size than the other magnetic inserts 325B, 325C, resulting in more heat being applied to the tip area of the screw 302 to ensure that the material within the cylinder 310 is sufficiently molten before flowing through a nozzle affixed to cylinder 310 into a mold cavity. The 325C insert can be of a smaller size than the other 325A, 325B magnetic inserts, resulting in less heat being applied to the screw 302 next to the hopper block 306. The 325A, 325B, 325C inserts can interact with the magnetic field of the electromagnet, such as inductive heating coil 340, to generate different amounts of heat along the length of screw 302, thereby applying different amounts of heat to the raw material located between screw 302 and cylinder 310.

[0057] Screw 302 can be formed of a magnetic material, and thus can interact with the magnetic field to create a baseline heat value for generating the raw material, and inserts 325A-325C can supplement heat generated by screw 302 to progressively heat the material along the length of screw 302. Inserts 325A-325C may vary in size according to the heat requirements of a particular molding application. In some embodiments, the 325A insert may be approximately 3/8" in diameter, the 325B insert may be approximately ^" in diameter, and the 325C insert may be approximately 3/16" in diameter. When using different sizes of inserts 325A, 325B, 325C, a single electromagnet (such as inductive heating coil 340) can be positioned around screw 302 and cylinder 310. Inserts 325A-325C can be formed at least partially from a magnetic material such as carbon steel.

[0058] Referring to FIGS. 2A-3C, the molding system 200, 300 may include a gripping nozzle 208, 308 at the end of the cylinder 210, 310. The molding system 200, 300 may include a screw tip 212, 312 adapted to the nozzle 208, 308 to seal the mouthpiece 208, 308 between shots. Screw tip 212, 312 can displace substantially all molten material from nozzle 208, 308 such that no cold raw mass can be formed within nozzle 208, 308. For example, as illustrated in FIGS. 2B and 3A-3C, the screw tip 212, 312 may include a substantially cylindrical tip portion for displacing material from within a nozzle opening or orifice 208, 308, and may further include an angled portion for displacing material from an interior surface of the nozzle 208, 308 extending radially outward from the orifice. The angled portion of the screw tip 212, 312 may include a conical or frustoconical leading surface for engagement with a corresponding interior surface of the nozzle 208, 308. The angled portion may extend outwardly and backwards from the tip portion. The combination of the screw tip portion and the angled portion of the screw tip 212, 312 can displace substantially all of the material from the nozzle 208, 308. The nozzle 208, 308 may extend into and engage the mold and thus may lose heat through engagement with the mold. By displacing substantially all of the material from the nozzle 208, 308, which may be cooled by the mold, the screw tip 212, 312 can restrict the formation of a cold raw mass in the nozzle 208, 308. The angled portion of the screw tip 212 , 312 can displace molten material a sufficient distance away from the nozzle orifice to ensure that the molding material near the front of the screw 208, 308 is at a desired melt temperature when the screw 202, 302 begins to rotate and extrude the material for the mold. A cylinder may be used behind the screw 202, 302 to ensure that the screw tip 212, 312 is seated in the nozzle 208, 308 to displace all molten material from the nozzle area. The nozzle switch 208, 308 can allow low pressure extrusion, due to the fact that no cold stock is formed, and thus, the traditional injection molding system 100 (see FIG. 1), a cold stock it does not need to be dislodged from the nozzle before injecting material into the mold. Screw tip 212, 312 may be placed against nozzle 208, 308 to seal or close nozzle 208, 308, which may be connected to one end of cylinder 210, 310. Extrusion screw 202, 302 may include a hollow portion such that a resistive heater or other heating device and thermocouple can be placed within the extrusion screw 202, 302. Details of the screw tip design are described in a U.S. Provisional Related Patent Application Number 62/087,449 (Ref. Number P249081.US.01), entitled “Nozzle Switch for Extrude-Fill Type Injection Molding System,” and in U.S. related number 14/960,115 entitled “Nozzle Switch for Injection Molding System”, filed December 4, 2015, and related Patent Application number PCT/US2015/064110 entitled “Nozzle Switch for Injection Molding System injection”, filed on December 4, 2015, whose orders are incorporated in this document by reference in their entirety.

[0059] The molding system 200, 300 may include a drive system for rotating the extrusion screw 202, 302. For example, the molding system 200, 300 may include an extrusion motor that rotates the screw 202, 302 and can be controlled by electric current to drive the screw rotation. The motor can drive the screw 202, 302 using a drive belt or chain. The molding system 200, 300 may include an extrusion motor that is axially aligned with the extrusion screw 202, 302 as a direct drive, making the molding system 200, 300 a discrete unit and facilitating the use of multiple molding systems. 200, 300, which may be described as extruders, in a single machine (eg, see FIG. 8). The molding system 200, 300 may include a cylinder that moves the screw tip 212, 312 to contact the inside of the mouthpiece 208, 308 or the mold port. The cylinder may move the extrusion screw 202, 302 forward with respect to the cylinder 210, 310 to bring the screw tip 212, 312 into contact with the nozzle 208, 308 so as to close or stop the nozzle 208, 308 or it may moving cylinder 210, 310 rearwardly with respect to screw 202, 302 so as to bring nozzle 208, 308 into contact with screw tip 212, 312 in order to close or stop nozzle 208, 308.

[0060] As shown in FIG. 2C, the extrusion screw 202 may have a constant root diameter 230 as opposed to the variable root diameter of the traditional extrusion screw 102 (see FIG. 1). The extrusion screw 202 may use a comparatively small pitch 234 instead of the large pitch 132 of the traditional extrusion screw 102, as shown in FIG. 1. The small pitch 234 can be designed to help pump material into the mold while the large pitch 132 of the traditional extrusion screw 102 is more suitable for providing shear heat generation.

[0061] Referring further to FIG. 2C, bolt dimensions, including bolt length, bolt root diameter, and 232 bolt fillet height, may affect shot size or part size or accuracy. For example, a large part can be molded by extruding with a screw including, for example, a long screw length, a large root diameter, or a high screw thread height 232. When the extrusion screw diameter becomes small , the volume of extruded plastic can be efficiently reduced, but the extruded volume control can be more precise, which helps to control that the shot size is consistent for each molding cycle.

[0062] The extrusion screw 202, 302 can be made of bronze or a bronze alloy, which have greater heat conduction capabilities than the steel commonly used in traditional injection molding system. A brass screw can conduct heat into the material better than a steel screw, and the material, such as plastic, can move more freely along its surface, promoting mixing. Bronze has a low coefficient of friction, which can help expand pumping efficiency, especially for molding sticky materials such as mixed/contaminated recycled resin, or starch-based resins. Pumping efficiency is a measure of the volume of material pumped into a mold per unit time.

[0063] Still referring to FIG. 2C, cylinder 210 may include a transition section 210B between a main section 210A and an inlet section 210C. Transition section 210B may have a smaller outside diameter configured to fit cylinder collar 220 including two portions 220A-220B. Inlet section 210C may include inlet 226 coupled to opening 216 of hopper block 206. Referring to FIG. 2A, 2B, and 2C, when molding system 200 is assembled, heaters 214A-214C may surround main section 210A of cylinder 210, and collar 220 may be seated in transition section 210B of cylinder 210. Portions 220A -220B of collar 220 may be positioned in transition section 210B of cylinder 210 and may be affixed to one another, for example, with fasteners threaded into holes 228A-228B formed in collar portions 220A-220B. When held together, collar portions 220A-220B can resist rotation of collar 220 relative to cylinder 210, and recessed transition section 210B of cylinder 210 can prevent axial movement of collar 220 along the length of cylinder 210. Collar 220 may be affixed to hopper block 206 to axially and rotatably secure hopper block 206 to cylinder 210. Cylinder collar 220 may be attached to hopper block 206, for example, using fasteners inserted through holes 227A- 227B formed in collar portions 220A-220B and threaded in holes 219 formed in hopper block 206 as shown in FIG. 2C. Hopper block 206 may include a hollow portion 217 configured to slide over cylinder section 210C. Hopper block 206 may be mounted to inlet section 210C of cylinder 210 such that opening 216 of hopper block 206 aligns with inlet 226 of inlet section 210C of cylinder 210 to provide a passage for material to enter. into cylinder 210 from hopper block 206. Screw 202 may be placed inside cylinder 210 and screw threads may extend from inlet section 210C of cylinder 210 to main section 210A of cylinder 210 in order to facilitate pumping material from inlet 226 of cylinder 210 towards nozzle 208.

[0064] Static heat conduction can facilitate automatic machine start-up for molding system 200, 300. Traditional injection molding machine 100 requires a purge process at start-up to generate enough shear heat to achieve the viscosity of the plastic before molding. More details are described in the related U.S. Patent Application. 62/087,480 (Reference Number P249082.US.01), titled “Control System for Injection Molding of the Extrude-Fill Type,” in the U.S. Patent Application. related number 14/960101 entitled “Control System for Injection Molding”, filed December 4, 2015, and related International Patent Application number PCT/US2015/064073 entitled “Control System for Injection Molding”, filed on December 4, 2015, the orders of which are incorporated herein by reference in their entirety.

[0065] The raw material, such as plastic, can be provided in the form of pellets. Pellets can be approximately 1/8” to 3/16” in diameter and length, and irregularities in size and shape are common. To accommodate the pellets, traditional injection molding systems have a hopper with a throat of a certain size to accept the pellets, and the extrusion screw can be sized for the diameter and pitch of the screw to receive the pellets from the hopper throat and efficiently pull the pellets into the extrusion cylinder. The need for pellet acceptance may dictate a minimum screw and cylinder size for the traditional 100 injection molding system, which may dictate the constant screw and cylinder size throughout the traditional 100 injection molding system.

[0066] The molding system 200, 300 can allow dynamic compaction and holding of a desired pressure in a mold cavity. In general, as the molten material in the mold begins to cool, it may contract, resulting in a part with reduced mass and/or inconsistent or non-uniform density. The molding system 200, 300 may monitor a parameter indicative of a pressure in the mold cavity via, for example, one or more sensors associated with the mold, the molding system, and/or the gripping system. For example, the molding system 200, 300 may receive real-time feedback from one or more sensors (such as a mold cavity pressure sensor, a screw back pressure sensor, a strain gauge frame, or other sensor) and may determine a real-time pressure in the mold cavity based on the output of one or more sensors. If the molding system 200, 300 detects a pressure drop in the mold cavity, the molding system 200, 300 may pump additional molten material into the mold cavity in order to maintain the desired pressure in the mold cavity, thereby displacing shrinkage and/or mass reduction of the molded part to ensure a more consistent and/or uniform part density throughout the entire molded part.

[0067] The molding system 200, 300 can keep the mouthpiece 208, 308 in an open configuration during the recompaction process, or the molding system 200, 300 can selectively open and close the mouthpiece 208, 308 during the recompaction process to allow or restrict, respectively, flow of molten material into the mold cavity. For example, the molding system 200, 300 can reverse the rotation directions of the screw 202, 302 in order to move the screw 202, 302 in an axial direction with respect to the nozzle 208, 308 and selectively open and close the nozzle 208, 308 with screw tip 212, 312. When nozzle 208, 308 is in an open configuration, screw 202, 302 may be selectively rotated to maintain substantially constant pressure in the mold cavity. The screw 202, 302 can be turned to pump additional molten material into the mold cavity until the desired pressure in the mold cavity is reached. The desired pressure in the mold cavity can be determined by the mold or part designer, and can be based on a desired material density of the molded part.

[0068] The molding system 200, 300 can selectively compact the mold to a desired part density, and then maintain that part density during cooling of the material within the mold cavity due at least in part to the elimination of a cold raw mass. , and thereby allowing free flow of material for extrusion on demand. In contrast, the traditional 100 injection molding system is a sequential, fixed process that culminates in a single injection throat, which requires a recovery stage in preparation for another injection cycle. Completion of the injection cycle of the traditional injection molding system 100 results in the formation of a cold raw mass in a nozzle opening, thereby preventing recompaction. Shot size modifications to the traditional 100 injection molding system require changes to control settings prior to the injection cycle. By compacting the mold to a desired part density, and then maintaining that part density while cooling the material within the mold cavity, the molded part density can be consistently repeated, thereby providing a higher level of dimensional stability. and strength of the molded part. Additionally, or as an alternative, wall sections thicker than those recommended in the molded part geometry can be achieved relative to the industry recommended molded wall thickness, resulting in increased strength of the molded part.

[0069] A stepped extrusion screw can be designed to accelerate the flow of material into the mold when faster filling speeds are desired. FIG. 4A illustrates a system 400 in accordance with the embodiments of the present description. FIG. 4B is a sectional view of the molding system 400 illustrated in FIG. 4A. FIG. 5 is a perspective view of the components of the molding system 400 illustrated in FIG. 4A before assembly.

[0070] Referring to FIGS. 4A-5, the molding system 400 may include an extrusion stepped screw 402. The inlet end of the extrusion stepped screw 402 may be of a size sufficient to receive pellets from the hopper 406, and the outside diameter of the screw 402 may be reduced along the length of the screw 402 towards the exit end of the screw 402, resulting in a corresponding reduction in the inner and outer diameter of the barrel 410. The stepped extrusion screw 402 and the barrel 410 can enable the exit ends appliance 400 fits into tighter or smaller areas, which can make it easier to locate the ports on the inside of certain molded parts, so the outer surface of the parts can be fully decorative, with the ports hidden from view in the inner surface of parts. In other words, by reducing the outside diameter of screw 402 and the inside and outside diameter of cylinder 410 as the material in cylinder 410 is heated up to melt the material, the reduced diameter of bolt 402 and cylinder 410 provides a reduction in the size of the exit end of the molding system 400 that makes it possible to use the molding system 400 in other areas that would otherwise be too small.

[0071] Referring further to FIGS. 4A-5, the extrusion stepped screw 402 and cylinder 410 can cause the molten material to advance out of the outlet or hot end of the molding system 400 because the material is forced to a smaller cross-sectional area which accelerates the flow rate. of material. Accelerated material flow can aid in mold filling with small and complicated setup without significantly reduced nozzle or mold opening port geometry and can reduce induced stress on the material and reduce part deformation.

[0072] Referring further to FIGS. 4A-5, the stepped extrusion screw 402 may be placed within the cylinder 410. The cylinder 410 may include a first section 410A and a second section 410B having a larger diameter than the first section 410A. A nozzle 408 may be coupled to one end of the first section 410A for releasing molten material into a mold. Cylinder 410 may include an end section 410C with an opening 426 for receiving raw material from a hopper block 406. Cylinder 410 may include a cylinder collar 410D that functions as a plug when the hopper block 406 is mounted with the cylinder 410.

[0073] Hopper block 406 may be coupled to end section 410C of cylinder 410. Hopper block 406 may include a top opening 416 with a sloping side wall for material to be fed into cylinder 410 through a defined inlet 426 in end section 410C. Hopper block 406 may include a hollow cylindrical portion 420 for sliding over cylinder end section 410C, and hopper block 406 may be placed against a cylinder collar 410D, which may be affixed to hopper block 406, for for example, using fasteners inserted into holes 419 formed in hopper block 406. Hopper block 406 may be cooled by circulating a cooling fluid, e.g., by circulating water, or other cooling compounds, through channels 418.

[0074] As shown in FIG. 5, the extrusion stepped screw 502 may have a constant root diameter 506, and may include a first section 508A with a first fillet height 502A, and a second section 508B with a second fillet height 502B. For example, the extrusion stepped screw 502 may include a first screw section 508A of a smaller fillet height 502A along the length of the screw 502 where the raw material is heated and melted. Changing from the larger fillet height to the smaller fillet height can increase material flow into the mold such that pumping efficiency increases. The stepped extrusion screw 502 may include a second section 508B of a greater fillet height 502B near the hopper where a raw material is drawn into the cylinder. The greater height of the screw thread 502B may be sufficient to feed into the cylinder from the hopper so that the material is more easily fed into the cylinder.

[0075] Pumping efficiency may vary with screw shape or geometry. For example, a screw 600A may include a thread or thread with substantially vertical side walls, and screw 600A may be described as a sharp screw. Screw fillet side walls 600A can extend away from a screw root 600A at a relatively small angle 602, as shown in FIG. 6A. The relatively small angle 602 can make it easier to feed material into the cylinder from the hopper, such as flake-type samples. Referring to FIG. 6B , a screw 600B may include a thread or thread with less vertical side walls than the thread of screw 600A in FIG. 6A, and screw 600B can be described as a less sharp screw. Screw fillet side walls 600B may extend away from a screw root 600B at a relatively large angle 604 that is greater than the angle 602 of screw 600A. The relatively large angle 604 of screw 600B can provide good mixing of material, including cold and hot material. A screw may include a first portion of the less acute geometry as shown in FIG. 6B near the mouthpiece and a second portion of the sharp geometry as shown in FIG. 6A next to the hopper (not shown). In some embodiments, screw threads positioned close to the hopper may be more vertical (eg, more perpendicular to a root diameter) than screw threads positioned close to the nozzle. For example, the extrusion screw can have a more vertical fillet geometry close to the hopper to receive pelletized material from the hopper and efficiently pull the pellets into the extrusion cylinder, an angularly shallower fillet geometry in the temperature transition region to mix cold and hot material together, and another fillet geometry change to mix and pump material along the final length of the screw towards the nozzle.

[0076] The screw may include variable pitches (eg multiple different pitches) along its length to provide different pumping and mixing characteristics along its length. For example, depending on the molding application, the screw may be designed with a relatively small pitch, a relatively large pitch, or a combination of pitches. The change in pitch along the length of the screw can be gradual, progressive or abrupt. For example, the pitch of the screw threads can gradually change (eg increase) along the length of the screw from the hopper to the location. Additionally, or alternatively, the bolt may include multiple sections defined along its length, and the sections may have different pitches relative to each other. For example, the extrusion screw may have a larger screw pitch to receive pellet material from the hopper and efficiently pull the pellets into the extrusion cylinder, a smaller screw pitch to mix hot and cold material together, and a even smaller screw to pump molten material along the length of the screw towards the nozzle. Referring to FIG. 5 , the first section 508A of the screw 502 may include a first pitch between adjacent screw threads, and the second section 508B of the screw 502 may include a second pitch between adjacent screw threads that is different from the first pitch. In some embodiments, the second pitch of the second section 508B may be greater than the first pitch of the first section 508A, because the second section 508B can pump pelletized material from the hopper toward the nozzle and the first section 508A can pump molten material toward the nozzle. nozzle.

[0077] FIG. 7 is a flowchart illustrating steps for molding a part in accordance with the embodiments of the present description. Method 700 begins with connecting one or more heaters to melt a material within the cylinder at step 702. The mold can be clamped by applying pressure at step 706.

[0078] Method 700 may include removing the bracket present behind the bolt. Extrusion can start with the initial rotation of the extrusion screw which can make the screw move axially with respect to the cylinder or the initial axial movement with the cylinder with respect to the screw to open the nozzle. The extrusion may continue with the rotation of the screw to pump the molten material into a mold until the mold is filled at operation 710. During pumping of the material into the mold, the extrusion screw may not have any axial movement. After filling the mold cavity, there may be a hold time to hold the extrusion pressure against the material in the mold. For example, the molding system 200, 300 can rotate the extrusion screw 202, 302 to apply a dynamic load on the material in the mold and maintain a desired part density. Screw 202, 302 can be moved axially with respect to cylinder 210, 310 to selectively open and close nozzle 208, 308 to respectively allow or prevent material from flowing into the mold cavity. As the material in the mold begins to cool, the molding system 200, 300 may open the nozzle 208, 308 and turn the screw 202, 302 to re-compact the mold, thereby compensating for part shrinkage as the material in the mold changes. cool. The ability to dynamically re-compact the mold is achievable, for example, due to the adapted geometry of the screw tip 212, 312 and nozzle 208, 308 preventing the creation of a cold raw mass and the on-demand extrusion capability of the molding system 200 , 300. By maintaining a desired pressure on the material in the mold, the molding system 200, 300 can ensure consistent part density and can eliminate common defects experienced with the traditional injection molding system 100, such as part shrinkage and surface depressions.

[0079] Method 700 may additionally include reverse rotation of the extrusion screw to decompress the cylinder and stop the non-Newtonian action of the material in operation 714. The reverse decompression cycle can stop pressure development in the cylinder. The decompression cycle can eliminate any hysteresis, and can readjust the molding system for a low motor torque requirement at an extrusion start. The decompression cycle can alleviate deforming stress on any component of the machine frame. The non-Newtonian action of the material can cause the material to absorb direct force and hurl itself outward against the cylinder wall, which can increase the force required to move the material in its intended path. The non-Newtonian action can be broken by reversing the rotation of the extrusion screw, which can allow continuous extrusion of the material under a low injection pressure, which can be from about 3.45 to about 10.34 MPa (500 psi at about 1,500 psi).

[0080] Method 700 may also include loosening the mold by releasing the pressure in operation 718. Afterwards, a molded part may be removed from the mold. For each molding cycle, the extrusion screw can rotate to move backward with respect to the cylinder or the cylinder can move forward with respect to the screw to open the nozzle and move the plastic forward to fill the mold. Then the screw can reverse rotation to move forward with respect to the cylinder or the cylinder can move backward with respect to the screw to close the nozzle.

[0081] The molding operation described above is different from the operation of the traditional injection molding system 100 (see FIG. 1). The present molding system does not include a recovery extrusion stage and an injection cycle like the traditional injection molding system 100. Referring to FIG. 1 again, the traditional molding process begins with rotating the extrusion screw 102 to agitate the plastic to generate shear heat while transferring the plastic to the front end of the screw 102. During the recovery extrusion stage, the plastic is moved forward and the extrusion screw 102 can move backwards a preselected distance, which affects the size of the shot in addition to the diameter of the screw. An injection cycle begins after the recovery extrusion stage. A large force is applied to the back of the extrusion screw 102 by an injection cylinder 138 to advance the extrusion screw 102, which dislodges the cold raw mass and evacuates the plastic in the injection zone 112. pressure

[0082] The 200, 300, 400 molding system can operate with much lower injection forces than the traditional 100 injection molding system. For example, the 200, 300, 400 molding system can generate the same pressure as the pressure in the mold cavity or a slightly higher injection pressure, such as a 5-10% increase in injection pressure, than the pressure in the mold cavity, which can range from 3.45 to 10.34 MPa (500 psi at 1,500 psi), for example. In contrast, an injection pressure of 137.90 to 206.84 MPa (20,000 and 30,000 psi) may be required for the traditional injection molding system 100 to provide the same pressure of 3.45 to 10.34 MPa (500 psi to 1,500 psi) to the mold cavity. As a result of the lower injection pressure, the total power requirement for the molding system may be, for example, 0.5 to 3 kilowatt hours of 110 volts or 208 volts of single-phase electrical power. In contrast, the traditional 100 injection molding system requires 6 to 12 kilowatt hours of 220 volts or 440 volts of three-phase electrical power.

[0083] Low injection pressure can reduce the grip pressure required for the mold. For example, the grip pressure can be approx. 10% higher than the pressure required in the mold cavity. As a result of the low grip pressure, the molds can be formed from a low cost material, such as aluminum, instead of steel for traditional molds. Injection and gripping pressure can reduce the size of the machine, which can reduce the financial and operating costs of the machine. The molding system can be much smaller than the traditional 100 injection molding system. Additionally, extrusion under a lower pressure can result in more uniformly molded parts with consistent density, which can reduce part warping and improve the quality of the product. product. The molding system may include a low pressure gripping system for the mold, which can reduce tooling damage due to the high grip pressure coming from the traditional injection molding system.

[0084] In some embodiments, the molding machine may include a gripping system including a front access or shuttle table (hereinafter "shuttle table" as a convenience and not intended to be limiting). The shuttle table can be used in association with a vertical gripping frame, and can facilitate operator access to a bottom half of a mold. The shuttle table can facilitate operator access to the mold outside of a gripping area, which can provide advantages when inserting molding and overmolding. The shuttle table can move along an axial direction of the molding machine, in contrast to a lateral movement of shuttle tables in traditional injection molding systems. The shuttle table can provide an operator with an open amount of time to inspect a molded part, reload a mold with multiple inserts, remove a part, or other functions.

[0085] The shuttle table can provide one or more advantages over the side-by-side shuttle table commonly used in traditional injection molding systems. The side-by-side shuttle table used in traditional injection molding systems requires the fabrication of two independent bottom mold halves. Once the cycle is complete and a first half of bottom mold is filled, the gripping press opens and the side-by-side shuttle table moves in a lateral direction to remove the first half of bottom mold from the gripping area. and pulling a second bottom mold half to the gripping area on a common launcher bed from the opposite lateral direction. This side-by-side movement of the shuttle table requires the operator (or automated positioning equipment) to move side-by-side around the machine to unload the finished part and reload the respective first and second bottom mold halves into the next injection cycle. This lateral movement is necessary because of the need for the traditional injection molding system to operate continuously in a fixed sequence cycle to prepare material using frictional pressure.

[0086] The front access shuttle table can allow an operator to access the mold with greater ease, flexibility, safety and/or visibility. Referring to FIGS. 8A and 8B, molding machine 800 may include molding system 801 (such as molding system 200, 300, 400 shown in FIGS. 2A-4B) and vertical gripping system 802. Gripping system 802 may include a shuttle table 803 that can be extracted from a gripping area 804 of the vertical gripping system 802 and can be reinserted back into the gripping area 804 dictated, for example, by the need and progress of the part being molded (such as as insert molded or overmoulded) and not dictated by the material processing (casting) requirements of the 800 molding machine. An operator workstation and operator activities can take up less space and be conducted in a safer manner because, for example, the operator can remain at a station and interface with the mold while the machine remains in an idle state. Shuttle table 803 can support a single bottom mold half, and therefore can accommodate reduced capital expenditure related to tooling cost and automated positioning equipment.

[0087] Referring further to FIGS. 8A and 8B, shuttle table 803 is accessible at an axial end of molding system 800 and can slide along an axial direction of molding machine 800. shuttle 803 is substantially positioned in gripping area 804 (see FIG. 8A), and an extended position, where shuttle table 803 is substantially removed from gripping area 804 (see FIG. 8B). When in the retracted position, shuttle table 803 may position a lower mold half 808 in gripping area 804 for conjugation with an upper mold half 810 to define a mold cavity for receiving molten material from nozzle 822 (such as such as nozzle 208, 308, 408 in Figures 2A-4B). As illustrated in FIG. 8A, when in the retracted position, shuttle table 803 can position lower mold half 808 in engagement with nozzle 822 of molding system 801. When in extended position, shuttle table 803 can remove lower mold half 808 from the area grip 804 to provide an operator with access to lower mold half 808. As illustrated in FIG. 8B, when in the extended position, shuttle table 803 can separate lower mold half 808 from mouthpiece 822 of molding system 801. As illustrated in FIGS. 8A and 8B, nozzle 822 may be coupled to cylinder 824 (such as cylinder 210, 310, 410 in FIGS. 2A-4B) of molding system 801.

[0088] Referring further to FIGS. 8A and 8B, shuttle table 803 is movable along a longitudinal axis 815 of molding system 801, such as cylinder 824. Shuttle table 803 is slidably coupled to a substantially horizontal press plate 812 of the machine. 800 for movement along longitudinal axis 815. Shuttle table 803 can be slidably mounted on a shuttle base 814, which can be fixedly attached to press plate 812. Shuttle base 814 can constrain the shuttle table 803 to move laterally with respect to platen 812, and can function as a rail to guide shuttle table 803 along longitudinal axis 815. Movement of shuttle table 803 can be controlled by a molding machine operator 800 For example, the molding machine 800 may include a control interface (such as a button) that controls the movement of the shuttle table 803. The control interface may allow the operator to slide Move shuttle table 803 into gripping area 804 for molding a part or out of gripping area 804 for access to lower mold half 808 and/or part received therein.

[0089] Shuttle table 803 may include a substantially flat upper surface 816 for supporting lower mold half 808. Upper surface 816 may be sized to support mold halves of different sizes, and may be positioned between vertical tie bars. 818 of molding machine 800. Upper mold half 810 may be attached to a substantially horizontal platen 820 of molding machine 800. Upper platen 820 may be movable in a vertical direction along connecting bars 818 to and against the lower platen 818 to mate and separate, respectively, the upper and lower mold halves 808, 810.

[0090] Still referring to FIGS. 8A and 8B, to mold a part, the movable press plates 820 can be moved along the vertical connecting bars 818 until the upper mold half 810 engages the lower mold half 808. A sufficient gripping grip can be applied to the mold halves 808, 810 to seal the interface between the mold halves 808, 810. Once the mold halves 808, 810 are sufficiently engaged with each other, the molding system 801 can extrude molten material into a mold cavity defined by mold halves 808, 810 until the mold cavity is filled. The molding machine 800 can monitor a parameter indicative of a pressure in the mold cavity (such as by a pressure transducer placed inside the mold cavity, a pressure transducer placed inside the cylinder of the molding system 801, a torque sensor measuring a screw torque of the molding system 801, an extensometer measuring a deforming force of a molding machine frame 800, or other parameter indicative of pressure), and can extrude additional material into the mold cavity if a loss of pressure is detected. pressure to maintain a desired cavity pressure and achieve a desired part density. The desired pressure can be determined based on various molding characteristics such as a part density recommended by the part designer), and the desired pressure can include a range of acceptable pressures. After a desired pressure has been maintained in the mold cavity for a predetermined time to allow the molten material in the mold cavity to cool sufficiently, a nozzle (e.g. nozzle 208, 308, 408 in FIGS. 2A-4B) can be closed. (e.g. by screw tip 212, 312 in FIGS. 2A-3C) and upper press plates 820 can be moved in a vertical direction along connecting bars 818 to separate upper and lower mold halves 808, 810. During or after separation of the mold halves 808, 810, the shuttle table 803 may slide along the axial direction 815 of the mold system 801 to move the lower mold half 808 away from the gripping area 804 in order to provide access for an operator to inspect a molded part remaining in the mold cavity of lower mold half 808. Shuttle table 803 is slidable along a substantially horizontal axis 815 from a molding position adjacent to an end. cylinder reference 824 (e.g. cylinders 210, 310, 410 in FIGS. 2A-4B) to an access position axially spaced from the end of cylinder 824.

[0091] The higher degree of injection force control, mold design flexibility, and machine design flexibility allows for a wider range of possibilities for producing plastic injection molding discrete parts and insert molded parts where discrete components or assemblies are placed in the injection mold and given plastic in the molding process.

[0092] In some embodiments, a single molding machine may include multiple ETF molding systems (such as molding system 200, 300, 400 in FIGS. 2A-4B), which can fill a multi-cavity mold (eg. example, multiple similar or different cavities) or a large mold cavity from multiple ports. The number of molding systems that can be included in a single mold or machine configuration can be unlimited. The positioning of molding systems is not limited to a common plane or traditional position, and each molding system can be seated, hung, suspended, etc. to accommodate specific plumbing requirements for a part or mold. Molding systems can be of similar or different size and screw design to accommodate mold or material demands for their respective outputs. Molding systems can be connected to a common material source, material source subgroups, or independent material sources to accommodate mold demands for their respective outputs. Molding systems can be controlled as a common group, subgroups, or independently to perform their respective functions and accommodate the mold demands for their respective outputs. Molding systems can be coordinated as a group, subgroups, or independently to synchronize machine functions controlled by a central or main microprocessor. Molding systems can have a similar or different heating and insulation configuration to accommodate mold or material demands for their respective outlets. Molding systems may have similar or different output feedback methods and sources to accommodate the mold demands for their respective outputs.

[0093] FIG. 9 is a simplified diagram illustrating a molding machine 900 including multiple molding systems 902 in accordance with the embodiments of the present description. Molding system 900 may include four separate molding systems 902 (hereinafter "extruders" for the purposes of convenience and not intended to be limiting), each of which may include sub-assemblies 904 (each of which may include a controller for the respective extruder 902) and corresponding inlets 906 connected to one or more hoppers to receive materials from the hoppers. Extruders 902 may be fed by gravity, vacuum, mixing screw, or other means to individual feed tubes or inlets 906. In some embodiments, inlets 906 may be connected to a single common hopper. For example, a single hopper may accept material, such as plastic pellets, and may use a series of feed tubes or inlets to convey the plastic pellets to individual extruders 902 to allow their independent functions within the machine 900. In some embodiments , the inlets 906 can be connected to a series of independent hoppers, and materials of a common nature but of different colors, or materials of a different nature, can be molded in a common machine cycle. Parts of different size and material type can be accommodated in a common cycle due to each of the 902 extruders operating and being controlled independently of each other. Each extruder 902 can be operated independently, but coordinated to ensure efficient molding as a coordinated system.

[0094] Referring to FIG. 9 , a single molding machine 900 can include multiple extruders 902 to fill a mold with a plurality of cavities (see, for example, FIG. 12) or a single cavity (see, for example, FIG. 13). Extruders 902 can extrude the same or different materials. The individual extruders 902 can be coupled to a single mold having multiple ports (see, for example, FIG. 13) to fill the mold portion. The combination may be desirable because, for example, the resin material in extruders 902 can be prepared for molding with extruders 902 in a static state. Each extruder 902 can be independently controlled. Each extruder 902 can provide individual feedback to its respective controller. Each extruder 902 can include pressure detection from a direct pressure sensor, from a torque load on a motor coupled to the respective injection system, from an amount of electricity consumed by the respective motor, from a strain gauge in a frame of the system. mold, or from other pressure sensing parameters. Each extruder 902 may be arranged as a closed loop system and may be individually controlled. A central or main microprocessor may process data received from extruders 902 and control each extruder 902 to individually or collectively cease material flow once a target pressure is reached. A central or main microprocessor may process data received from individual extruders 902 to sequentially, simultaneously or otherwise activate individual extruders 902 to provide progressive function. The 900 extrusion molding system can be a closed-loop system that features an output-based, sensor-defined process that allows the use of any combination of 902 extruders. of consistent part, which can lead to accurate and consistent dimensions for molded parts, and can reduce bending of plastic parts. The molding system 900 can be more efficient than the traditional injection molding system 100, which releases plastic from a single nozzle through multiple feed channel branches, each branch causing a pressure loss that requires a much higher initial injection. The higher injection force of the traditional 100 injection molding system requires more power and a more massive machine with higher operating costs while providing uneven plastic temperature and viscosity.

[0095] Referring to FIG. 9, a single molding machine 900 can produce individual molded parts of similar or different geometry, material type or color from the two or more mold cavities using two or more independent operating extruders 902 individually aligned for each independent cavity within the mold. mold. Each extruder 902 can be independently controlled. When used for parts of common geometry or material type, each extruder 902 can provide individual feedback to its respective controller to ensure uniformity in each mold cavity and provide accurate part density and product quality. When used for parts of different geometry or material type, each extruder 902 can provide individual feedback to its respective controller to ensure that different requirements are met for each independent mold cavity. Each 902 extruder can have pressure detection from a direct pressure sensor, from a torque load on a motor coupled to the respective injection system, from an amount of electricity consumed by the respective motor, or from other parameters. pressure detection. Each extruder 902 may be arranged as a closed loop system for each respective mold cavity, collecting data from and related to the individual mold cavity, and may be individually controlled. A central or main microprocessor may process data received from injection systems 902, and may individually stop material flow and collectively open and close the mold based on data received from individual injection systems 902.

[0096] The 900 molding machine can be a highly efficient, compact, self-contained assembly that fits into a small contact surface and allowing the individual 902 extruders to be used in close proximity to each other. The molding machine 900 can be a closed-loop system that features a sensor-defined, output-based process that allows the use of any combination of 902 extruders. consistent part and uniform weight, which can lead to accurate and consistent dimensions for individual but common molded parts and can improve performance when used in highly automated assembly operations. 902 extruders can allow the molding of discrete parts with different material, density and weight requirements, which can be discrete items or can be used in common assemblies to improve the efficiency of assembly operations or reduce part costs by amortizing manufacturing costs. tooling arising from multiple different parts. The 900 molding machine can be more efficient than the traditional 100 injection molding system, which releases plastic from a single nozzle through multiple channel branches, each branch causing a pressure loss that requires injection force. much higher starting point. The high injection force of the traditional 100 injection molding system requires more power and a more massive machine with higher operating costs while providing uneven temperature and viscosity resulting in inconsistent individual part uniformity.

[0097] The molding machine 900 may include a frame including vertical press plates 908A-908C and horizontal bars 910A-910D at four corners of each press plate 908A-908C. Press plates 908A-908C can be connected by horizontal bars 910A-910D passing through holes in press plates 908A-908C. Vertical press plates 908A-908C may be substantially parallel to each other and may be spaced along horizontal bars 910A-910D, which may be substantially parallel to each other. A mold can be placed between press plates 908A and 908B. The position of platen 908B can be adjustable along bars 910A-910D to accommodate a mold of a particular size. The frame can be assembled by clamping bars 910A-910D against press plates 908A and 908C at the two opposite ends of bars 910A-910D.

[0098] Referring to FIG. 10, a molding machine 1000 may include multiple extruders 902 coupled to a manifold 1004. The manifold 1004 may support the extruders 902 relative to one another and may be coupled to a hopper 1008. The hopper 1008 may be placed on top of the manifold 1004 to facilitate the distribution of molding material (such as cold pellets) to the individual extruders 902. Each extruder 902 may include an independent drive system (such as a motor) and independent controls for operating the respective extruder 902. Each extruder 902 may include a screw (such as screw 202, 302, 402, 502 in Figures 2A-5) rotatably positioned within a cylinder 1012 (such as cylinder 210, 310, 410 in Figures 2A-5). Each extruder 902 may include one or more heaters, which may include external heaters 1016 (such as the belt heaters 214 in Figures 2A-2C and/or the inductive heating coil 340 in Figures 3A-3C) and/or the internal heaters (such as resistive heater 225 in Figures 2B and/or inserts 325 in Figures 3A-3C). Each extruder 902 may be coupled to the manifold 1004 via a thrust bracket housed in the manifold 1004. Each extruder 902 may include an independent valved port nozzle 1020 (such as nozzle 208, 308, 408 in FIGS. 2A-4B) for controlling the flow of resin material, such as plastic, into a mold cavity associated with nozzles 1020.

[0099] Referring to FIG. 11, raw material (such as cold plastic pellets) may be loaded into hopper 1008. Raw material may flow through a flow path 1024 defined in manifold 1004 from hopper 1008 to individual extruders 902. Raw material may enter the extruders 902 through the inlet ports (such as the cylinder inlet 226 illustrated in FIGS. 2B and 2C). Raw material may be gravity fed from hopper 1008, through manifold 1004, and to each extruder 902. Flow path 1024 may include a single channel or throat 1028 extending down from hopper 1008 to an upper portion of the manifold. 1004. The throat 1028 may be divided into one or more branches 1032, with each branch 1032 of the flow path 1024 being in fluid communication with a respective inlet port of an individual extruder 902. The flow path 1024 may include different arrangements. depending on the arrangement and orientation of extruders 902 relative to manifold 1004. Extruders 902 may be oriented substantially parallel to each other and substantially perpendicular to manifold 1004, as illustrated in FIGS. 10 and 11, or extruders 902 may be oriented non-parallel to each other and/or non-perpendicular to manifold 1004 depending on the configuration of an associated mold. The extruders 902 can be arranged in a die with the extruders 902 forming vertical columns and horizontal rows of extruders, or the extruders 902 can be arranged in a dieless arrangement depending on the configuration of an associated mold.

[00100] Extruders 902 can extrude material into the same cavity of a mold half or to different mold cavities of a mold half. Referring to FIG. 12, molding machine 1000 includes a mold half 1036 defining multiple mold cavities 1040. Each extruder 902 is in fluid communication with a different mold cavity 1040 from mold half 1036 through a mold port 1044. Each extruder 902 may receive raw material from hopper 1008, melt the raw material, and then extrude the material into respective mold cavities 1040, which may be similar in geometry to one another, as illustrated in FIG. 12 or may differ in geometry. Each extruder 902 may include an independent controller monitoring the pressure in the respective mold cavity 1040, and the controller may cease extrusion of the respective extruder 902 once a desired pressure is reached in the respective mold cavity 1040. After all cavities 1040 present in the mold half 1036 have reached their desired pressures, a master controller can release a gripping press applied to the respective mold halves and can separate the mold halves to release the molded parts.

[00101] Referring to FIG. 13, molding machine 1000 includes a mold half 1052 defining a single mold cavity 1056. Each extruder 902 is in fluid communication with the same mold cavity 1056 as mold half 1052 through separate mold ports 1060. Each extruder 902 may receive raw material from hopper 1008, melt the raw material, and then extrude the material into the same mold cavity 1056. Each extruder 902 may include an independent controller monitoring the pressure in the area surrounding the extruder's mold port 1060. 902, and the controller may cease extrusion of the respective extruder 902 once a desired pressure is reached in the respective portion of the mold cavity 1056. After all extruders 902 have reached two desired pressures, a master controller may release a grip applied to the respective mold halves and can separate the mold halves to release the molded parts. In some embodiments, a master controller can control independent extruders 902 based on one or more pressures associated with mold cavity 1056. Extruders 902 can work together to fill mold cavity 1056 and can achieve consistent part density. providing greater dimensional stability.

molding materials

[00102] The generation and conduction of static heat used in the molding system may be insensitive to the material or properties of the resin, including, but not limited to, the grade, purity, uniformity, and melt flow rate of the resin, among others. For example, the molding system may be capable of molding any thermoplastic materials, such as co-associated/blended post-consumer recycled plastics, a blend of resins with different melt flow rates. Coming from different plastic classifications or chemical families, bio-based materials each of which are difficult to mold with the traditional injection molding system. And as a further example, a blend including two or more resins from different pellets can be blended to form a part. Multiple plastics may have different processing characteristics, such as melt flow rate, melt temperature, glass transition temperature, but the co-association of these materials may not present problems related to the molding system. Recycled plastics may include, but are not limited to, polyethylene (PE), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), nylon (PA), polycarbonate (PC), polylactic acid (PLA), styrene butadiene acrylonitrile (ABS), polysulfone (PS), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyetherimide (PEI), acrylic (PMMA), among others.

[00103] The molding system may be able to mold reinforced plastics with mineral fillers or fiber contents much higher than traditional injection molding machines can process. In general, it is difficult to mold reinforced plastic with 50% by volume of fiberglass or more by the traditional injection molding system 100, due to its safety in the generation of shear heat which is based on resins that have 70% by volume or more than petroleum-derived compounds. Using static heat generation in the present molding system, the melt may not be based on any petroleum-derived resin content. For example, reinforced plastic may contain more than 50% by volume of glass fibers, cellulose fibers, mineral aggregate or carbon fibers.

[00104] The present molding system may be less susceptible to wear degradation unlike the traditional injection molding system due to static heat conduction. Static heat generation can provide precise temperature control, which can help prevent material overheating. The extrusion screw can be sized to vary screw length and screw root diameter to control residence times and prevent or reduce thermal degradation.

[00105] The present injection molding system can be used for temperature and pressure molding of sensitive bio-based resins or plastics that are sensitive to wear degradation. Bio-based resins include cellulose materials, plant starch resins and sugar-based resins, which can be used for products such as medical implants, including but not limited to bone screws, bone replacements, stents, between others. The present molding system can also be used for injection molding of temperature and pressure/shear (MIM) sensitive metal. Raw materials for MIM can be sensitive to temperatures, residence times, and shear pressure, like bio-based resins. The present molding system can mold polymers with up to 80% loading volume from stainless steel or other metals. The present molding system can be used for injection of pasta, which can be extruded in molds heated to cooking temperatures to form food products of desired shapes. Molding materials may include, but are not limited to, amorphous thermoplastics, crystalline and semi-crystalline thermoplastics, virgin resins, fiber reinforced plastics, recycled thermoplastics, industrialized recycled resins, post-consumer recycled resins, blended and co-associated thermoplastic resins, organic resins, organic food compounds, carbohydrate-based resins, sugar-based compounds, gelatin/propylene glycol compounds, starch-based compounds, and metal injection molding (MIM) raw materials.

[00106] Having described various embodiments, it will be recognized by those skilled in the art that various modifications, alternative constructions and equivalents may be used without departing from the spirit of the invention. Additionally, a number of well-known processes and elements have not been described in order to avoid unnecessarily obscuring the present invention. Therefore, the above description should not be taken as limiting the scope of the invention. All the features described can be used separately or in various combinations with each other.

[00107] Those skilled in the art will recognize that the present invention described teaches by way of example and not by way of limitation. Accordingly, the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described in this document, as well as all statements of the scope of this method and system, which, in terms of language, could be said to cover the scope of the application.

Claims (38)

1. Molding machine (900, 1000), characterized in that it comprises: a first mold half (1036); two or more extruders (902) associated with the first mold half (1036), each extruder of the two or more extruders (902) including a cylinder (210, 310, 410, 824, 1012), an extrusion screw (202, 302) , 402, 502) within the cylinder (210, 310, 410, 824, 1012) and a nozzle (208, 308, 408, 1020) in sealed engagement with the first mold half (1036), wherein each extruder of the two or more extruders (902) is independently controlled to rotate the extrusion screw (202, 302, 402, 502) in a first direction to cause material flow and to rotate the extrusion screw (202, 302, 402, 502) in a second direction opposite the first direction for ceasing material flow once a target pressure is reached for the respective extruder (902); and a central or main microprocessor configured to process data received from the two or more extruders (902) and control each extruder to individually or collectively cease material flow once the target pressure is reached. 2. Molding machine (900, 1000) according to claim 1, characterized in that the rotation of the extrusion screw (202, 302, 402, 502) in the second direction occurs during a movement of the extrusion screw (202 , 302, 402, 502) in an axial direction towards the nozzle (208, 308, 408, 1020). 3. Molding machine (900, 1000) according to claim 2, characterized in that each extruder of the two or more extruders (902) is independently controlled to rotate the extrusion screw (202, 302, 402, 502) in the second direction until a tip (212, 312) of the extrusion screw (202, 302, 402, 502) is seated in the nozzle (208, 308, 408, 1020) to displace all material from the nozzle and to stop flow of material through the nozzle (208, 308, 408, 1020). 4. Molding machine (900, 1000) according to claim 1, characterized in that: the first half of the mold (1036) defines a single cavity of the mold (1056); and each extruder of the two or more extruders (902) is in fluid communication with the single mold cavity (1056). 5. Molding machine (900, 1000) according to claim 1, characterized in that: the first half of the mold (1036) defines two or more mold cavities (1040); and each extruder of the two or more extruders (902) is in fluid communication with a mold cavity other than the two or more mold cavities (1040). 6. Molding machine (900, 1000) according to claim 1, characterized in that it additionally comprises a single hopper (1008) operatively coupled to the two or more extruders (902) to supply material to the two or more extruders (902 ). 7. Molding machine (900, 1000) according to claim 6, characterized in that it additionally comprises a collector (1004) operatively coupled to the single hopper (1008) and to the two or more extruders (902) to divert the material to the respective extruders of the two or more extruders (902). 8. Molding machine (900, 1000) according to claim 1, characterized in that the two or more extruders (902) are arranged in a matrix. 9. Molding machine (900, 1000) according to claim 1, characterized in that: the two or more extruders (902) are oriented substantially parallel to each other; and at least two of the two or more extruders (902) are positioned one above the other along a vertical dimension of the first mold half (1036). 10. Molding machine (900, 1000) according to claim 1, characterized in that it additionally comprises a controller monitoring the pressure for each extruder of the two or more extruders (902) and configured to release a gripping force applied to the first half of the mold (1036) to release a part molded therein once each extruder of the two or more extruders (902) reaches its target pressure. 11. Molding machine (900, 1000) according to claim 1, characterized in that the target pressure for each extruder of the two or more extruders (902) is based on the area of the first mold half (1036) in which the respective extruder is extrusion material. 12. Molding machine (900, 1000) according to claim 1, characterized in that the two or more extruders (902) comprise four or more extruders spaced apart. 13. Molding machine (900, 1000) according to claim 1, characterized in that the two or more extruders (902) are identical to each other. 14. Molding machine (900, 1000) according to claim 1, characterized in that the two or more extruders (902) are different from each other. 15. Molding machine (900, 1000) according to claim 1, characterized in that the two or more extruders (902) are operable to extrude the same material or different materials into the first half of the mold (1036). 16. A method of molding a part, characterized in that it comprises: extruding a first material through a first nozzle (208, 308, 408, 1020) of a first extruder (902) in sealed engagement with a first mold half ( 1036) by rotating a first extrusion screw (202, 302, 402, 502) of the first extruder (902) in a first direction; extruding a second material through a second nozzle (208, 308, 408, 1020) of a second extruder (902) in sealed engagement with the first mold half (1036) by rotating a second extrusion screw (202, 302) , 402, 502) of the second extruder (902) in the first direction; ceasing extrusion of the first material through the first nozzle (208, 308, 408, 1020) when a first pressure associated with the first extruder (902) is achieved by rotating the first extrusion screw (202, 302, 402, 502) in a second opposite direction to the first direction; ceasing extrusion of the second material through the second nozzle (208, 308, 408, 1020) when a second pressure associated with the second extruder (902) is achieved by rotating the second extrusion screw (202, 302, 402, 502) in the second direction ; and releasing a molded part from the first mold half (1036) after the first and second pressures are reached. A method as claimed in claim 16, characterized in that it further comprises moving the first and second extrusion screws (202, 302, 402, 502) in an axial direction towards the first and second nozzles (208, 308, 408, 1020), and by rotating the first and second extrusion screws (202, 302, 402, 502), respectively, in the second direction. 18. Method according to claim 17, characterized in that turning the first and second extrusion screws (202, 302, 402, 502) in the second direction comprises moving the first and second extrusion screws (202, 302, 402). , 502) in the axial direction until the first and second tips (212, 312) of the first and second extrusion screws (202, 302, 402, 502) are seated in the first and second nozzles (208, 308, 408, 1020) to displace all material from the first and second nozzles (208, 308, 408, 1020) and to stop the flow of material through the first and second nozzles (208, 308, 408, 1020), respectively. 19. Method according to claim 16, characterized in that the extrusion of the first material and the extrusion of the second material comprises extrusion of the first and second material in the same cavity (1040) defined by the first half of the mold (1036) . Method according to claim 16, characterized in that the extrusion of the first material and the extrusion of the second material comprises extrusion of the first and second materials into different cavities (1040) defined by the first half of the mold (1036). 21. Method according to claim 16, characterized in that the first pressure is different from the second pressure. 22. Method according to claim 16, characterized in that the first extruder (902) is identical to the second extruder (902). 23. Molding machine (900, 1000), characterized in that it comprises: a mold (1036) defining a mold cavity (1040); an extruder (902) associated with the mold (1036), the extruder (902) including a barrel (210, 310, 410, 824, 1012), an extrusion screw (202, 302, 402, 502) within the barrel ( 210, 310, 410, 824, 1012) and a mouthpiece (208, 308, 408, 1020) in sealed engagement with the mold (1036); a sensor associated with the extrusion screw (202, 302, 402, 502) for detecting a torque load, the sensor being configured to provide a real-time response to a parameter indicative of a real-time pressure in the mold cavity ( 1040); and a controller configured to monitor the parameter and control the extruder (902) to rotate the extrusion screw (202, 302, 402, 502) in a first direction to cause material to flow into the mold cavity (1040) and into rotating the extrusion screw (202, 302, 402, 502) in a second direction opposite the first direction to stop the flow of material after a target pressure associated with the extruder (902) is reached. 24. Molding machine (900, 1000) according to claim 23, characterized in that the target pressure comprises a pressure within the mold cavity (1040). 25. Molding machine (900, 1000) according to claim 23, characterized in that the controller is configured to release a gripping force applied to the mold (1036) to release a part molded therein after the target pressure is reached . 26. Molding machine (900, 1000) according to claim 23, characterized in that the controller is coupled with the sensor and is configured to determine a real-time pressure in the mold cavity (1040) based on the parameter . 27. Molding machine (900, 1000) according to claim 23, characterized in that the controller is configured to control the extruder (902) to stop rotation of the extrusion screw in the first direction to allow material into the mold (1040) to cool before turning the extrusion screw (202, 302, 402, 502) in the second direction. 28. Molding machine (900, 1000) according to claim 23, characterized in that the controller is configured to control the extruder (902) to rotate the extrusion screw (202, 302, 402, 502) in the first direction after rotation of the extrusion screw (202, 302, 402, 502) and before rotating the extrusion screw (202, 302, 402, 502) in the second direction in response to a pressure drop in the mold cavity ( 1040). 29. Molding machine (900, 1000) according to claim 23, characterized in that rotation of the extrusion screw (202, 302, 402, 502) in the second direction causes a tip (212, 312) of the extrusion screw (202, 302, 402, 502) is seated in the nozzle (208, 308, 408, 1020) to evacuate material from the nozzle (208, 308, 408, 1020). 30. Molding machine (900, 1000) according to claim 23, characterized in that it further comprises a pressure transducer positioned inside the mold cavity (1040) or cylinder and configured to provide another measurement indicative of the real-time pressure in the mold cavity (1040) to the controller. 31. Molding machine (900, 1000) according to claim 23, characterized in that it further comprises an strain gauge positioned on a frame of the molding machine (900, 1000) and configured to provide another indicative measurement of pressure in time real in the mold cavity (1040) to the controller. 32. Method for molding a part with a molding machine (900, 1000), characterized in that it comprises: extruding material through a nozzle (208, 308, 408, 1020) of an extruder (902) in sealed engagement with a mold (1036) by rotating an extrusion screw (202, 302, 402, 502) of the extruder (902) in a first direction; measuring, by a torque sensor associated with the extrusion screw (202, 302, 402, 502), a parameter indicative of real-time pressure in a mold cavity (1040) of the mold (1036); monitor, by a controller, the parameter; ceasing extrusion of material through the nozzle (208, 308, 408, 1020) when a pressure associated with the extruder (902) is achieved by rotating the extrusion screw (202, 302, 402, 502) in a second direction opposite to the first direction ; and releasing a molded part from the mold (1036) after pressure is reached. 33. Method according to claim 32, characterized in that the parameter comprises a target pressure in a mold cavity (1040) defined by the mold (1036). 34. Method according to claim 32, characterized in that it further comprises determining, by the controller, the real-time pressure in the mold cavity (1040) based on the parameter. A method as claimed in claim 32, further comprising stopping the rotation of the extrusion screw (202, 302, 402, 502) in the first direction to allow the material in the mold to cool before rotating the extrusion screw ( 202, 302, 402, 502) in the second direction. 36. Method according to claim 35, characterized in that it further comprises rotating the extrusion screw (202, 302, 402, 502) in the first direction after stopping the rotation of the extrusion screw (202, 302, 402, 502) and before rotating the extrusion screw (202, 302, 402, 502) in the second direction in response to detection of a pressure drop in the mold cavity (1040). 37. Method according to claim 32, characterized in that the step of ceasing extrusion of material through the nozzle (208, 308, 408, 1020) comprises seating a tip (212, 312) of the extrusion screw (202, 302, 402, 502) into the nozzle (208, 308, 408, 1020) to evacuate material from the nozzle (208, 308, 408, 1020). 38. Method according to claim 32, characterized in that it further comprises monitoring, by the controller, another parameter indicative of a real-time extension of the molding machine (900, 1000).

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